The Question of Electrophilic vs Nucleophilic Addition of Cyclic β-Dicarbonyl Phenyliodonium Ylides: Electrophilic Cycloaddition of Diphenylketene

Antos, Anna; Elemes, Yiannis; Michaelides, Adonis; John, Anthony; Skoulika, Stavroula; Hadjiarapoglou, Lazaros P.

doi:10.1021/jo3020787

Cited by 23 publications

(9 citation statements)

References 36 publications

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“…It is well described as containing a dicoordinated positively charged iodine atom carrying two carborane anion substituents. All bond lengths and valence angles are unexceptional except for the B–I–B valence angle, which is 132.8° instead of the usual ∼97°. , …”

Section: Resultsmentioning

confidence: 92%

“…All bond lengths and valence angles are unexceptional except for the B−I−B valence angle, which is 132.8°instead of the usual ∼97°. 30,31 In contrast, the calculated geometry of the ylide radical is unsymmetrical, with one of the carborane cages best described as a radical (total cage charge +0. 22 The expected reversible oxidation potential of the iodonium ylide anion/radical redox couple was estimated from the adiabatic electron detachment energy of 6.16 eV calculated from the energy difference of the anion and the neutral radical of the iodonium ylide in acetone, whose dielectric properties resemble those of liquid SO 2 .…”

Section: ■ Introductionmentioning

confidence: 95%

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Electrochemical Oxidation of [1-X-12-I-CB₁₁Me₁₀^–] Anions: Formation of Borenium Ylides [12-Dehydro-1-X-CB₁₁Me₁₀] and Iodonium Ylide Anions [{12-(1-X-CB₁₁Me₁₀^–)}₂I⁺]

et al. 2016

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Cyclic voltammograms of 12-iodinated icosahedral carborane anions [1-X-12-I-CBMe] (X = H, CH, CH, CH, CH, CH, and COOCH) show two one-electron anodic oxidation peaks at the Pt electrode in liquid SO. Oddly, the first is irreversible and the second partially reversible. Mass spectrometry of the principal anionic product of preparative anodic oxidation of [1-H-12-I-CBMe], identical with the anionic product of its reaction with [EtSi-H-SiEt] and/or EtSi, allows it to be identified as the iodonium ylide anion [{12-(1-H-CBMe)}I]. Its reversible oxidation to a neutral ylide radical [{12-(1-H-CBMe)}{12-(1-H-CBMe)}I] is responsible for the second peak. A DFT geometry optimization suggests that both the ylide anion and the ylide radical are very crowded and have an unusually large C-I-C valence angle of ∼132°; they are the first compounds with two bulky highly methylated CB cages attached to the same atom. Molecular iodine is another product of the electrolysis. We propose an electrode mechanism in which initial one-electron oxidation of [1-X-12-I-CBMe] is followed by a transfer of an iodine atom from the B-I bond to SO to yield a weakly bound radical ISO which disproportionates into SO and I. The other product is the borenium ylide [12-dehydro-1-X-CBMe], which has a strongly Lewis acidic naked vertex in position 12 that rapidly adds to another [1-X-12-I-CBMe] anion to form the observed stable ylide anion [{12-(1-X-CBMe)}I]. In acetonitrile, where it presumably exists as a solvent adduct, [12-dehydro-1-X-CBMe] has been trapped with HO and, to a small extent, with MeOH, but not with several other potential trapping agents.

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Section: Resultsmentioning

confidence: 92%

Section: ■ Introductionmentioning

confidence: 95%

Electrochemical Oxidation of [1-X-12-I-CB₁₁Me₁₀^–] Anions: Formation of Borenium Ylides [12-Dehydro-1-X-CB₁₁Me₁₀] and Iodonium Ylide Anions [{12-(1-X-CB₁₁Me₁₀^–)}₂I⁺]

et al. 2016

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“…λ 3 -Iodanes and -bromanes show bonding patterns which can be rationalized as the formation of halogen-bonded systems, for instance, when an anion and/or a lone-pair-possessing heteroatom enters the σ-hole(s) on the halogen of a diaryliodonium or (aryl)alkynyliodonium salt (Figure ). − …”

Section: Nature Of the Halogen Bondmentioning

confidence: 99%

The Halogen Bond

et al. 2016

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The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

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“…Dimedone-derived iodonium ylides have been used in numerous synthetic transformations leading to various heterocyclic compounds. ,− For example, the fused dihydrofuran derivatives 495 can be obtained from iodonium ylide 493 and alkenes 494 under photochemical activation in high yields (Scheme ). The reaction using iodonium ylide 493 generated in situ from DIB and 1,3-cyclohexanedione under photochemical conditions gave products 495 in similar yields.…”

Section: Synthetic Applications Of Trivalent Iodine Compoundsmentioning

confidence: 99%

Advances in Synthetic Applications of Hypervalent Iodine Compounds

2016

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The preparation, structure, and chemistry of hypervalent iodine compounds are reviewed with emphasis on their synthetic application. Compounds of iodine possess reactivity similar to that of transition metals, but have the advantage of environmental sustainability and efficient utilization of natural resources. These compounds are widely used in organic synthesis as selective oxidants and environmentally friendly reagents. Synthetic uses of hypervalent iodine reagents in halogenation reactions, various oxidations, rearrangements, aminations, C−C bond-forming reactions, and transition metal-catalyzed reactions are summarized and discussed. Recent discovery of hypervalent catalytic systems and recyclable reagents, and the development of new enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important achievement in the field of hypervalent iodine chemistry. One of the goals of this Review is to attract the attention of the scientific community as to the benefits of using hypervalent iodine compounds as an environmentally sustainable alternative to heavy metals.

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The Question of Electrophilic vs Nucleophilic Addition of Cyclic β-Dicarbonyl Phenyliodonium Ylides: Electrophilic Cycloaddition of Diphenylketene

Cited by 23 publications

References 36 publications

Electrochemical Oxidation of [1-X-12-I-CB₁₁Me₁₀^–] Anions: Formation of Borenium Ylides [12-Dehydro-1-X-CB₁₁Me₁₀] and Iodonium Ylide Anions [{12-(1-X-CB₁₁Me₁₀^–)}₂I⁺]

Electrochemical Oxidation of [1-X-12-I-CB₁₁Me₁₀^–] Anions: Formation of Borenium Ylides [12-Dehydro-1-X-CB₁₁Me₁₀] and Iodonium Ylide Anions [{12-(1-X-CB₁₁Me₁₀^–)}₂I⁺]

The Halogen Bond

Advances in Synthetic Applications of Hypervalent Iodine Compounds

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The Question of Electrophilic vs Nucleophilic Addition of Cyclic β-Dicarbonyl Phenyliodonium Ylides: Electrophilic Cycloaddition of Diphenylketene

Cited by 23 publications

References 36 publications

Electrochemical Oxidation of [1-X-12-I-CB11Me10–] Anions: Formation of Borenium Ylides [12-Dehydro-1-X-CB11Me10] and Iodonium Ylide Anions [{12-(1-X-CB11Me10–)}2I+]

Electrochemical Oxidation of [1-X-12-I-CB11Me10–] Anions: Formation of Borenium Ylides [12-Dehydro-1-X-CB11Me10] and Iodonium Ylide Anions [{12-(1-X-CB11Me10–)}2I+]

The Halogen Bond

Advances in Synthetic Applications of Hypervalent Iodine Compounds

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Product

Resources

About

Electrochemical Oxidation of [1-X-12-I-CB₁₁Me₁₀^–] Anions: Formation of Borenium Ylides [12-Dehydro-1-X-CB₁₁Me₁₀] and Iodonium Ylide Anions [{12-(1-X-CB₁₁Me₁₀^–)}₂I⁺]

Electrochemical Oxidation of [1-X-12-I-CB₁₁Me₁₀^–] Anions: Formation of Borenium Ylides [12-Dehydro-1-X-CB₁₁Me₁₀] and Iodonium Ylide Anions [{12-(1-X-CB₁₁Me₁₀^–)}₂I⁺]